This kind of technology in the prior art includes a “cooling device” as disclosed in Japanese Patent Unexamined Publication No. 2003-8264. The cooling device disclosed in Japanese Patent Unexamined Publication No. 2003-8264 includes a plurality of heat dissipation members extending in the direction away from an electronic component. Cooling fluid is allowed to pass through between the respective heat dissipation members, thereby cooling the electronic component. The heat dissipation member is designed to have its length decreased as the heat transfer temperature of heat generated by the electronic component becomes lower.
It is described that the heat dissipation members are formed to become shorter from the center of the electric component toward the end thereof and along the flow direction of the cooling fluid.
However, the cooling device disclosed in the above Japanese Patent Unexamined Publication No. 2003-8264 includes the heat dissipation members extending in the direction away from the electronic component, and is designed to cool the electronic component by increasing a flow contact area with the heat dissipation member, which might inhibit reduction in size of the cooling device.